Chemical deposition raw material including heterogeneous polynuclear complex and chemical deposition method using the chemical deposition raw material

Abstract

The present invention relates to a chemical deposition raw material including a heterogeneous polynuclear complex in which a cyclopentadienyl and a carbonyl are coordinated to a first transition metal and a second transition metal as central metals, the chemical deposition raw material being represented by the following formula. In the following formula, the first transition metal (M.sub.1) and the second transition metal (M.sub.2) are mutually different. The number of cyclopentadienyls (L) is 1 or more and 2 or less, and to the cyclopentadienyl is coordinated one of a hydrogen atom and an alkyl group with a carbon number of 1 or more and 5 or less as each of substituents R.sub.1 to R.sub.5. With the chemical deposition raw material of the present invention, a composite metal thin film or a composite metal compound thin film containing plural metals can be formed from a single raw material. ##STR00001##

Claims

1. A method for chemical deposition of a composite metal thin film or a composite metal compound thin film, comprising vaporizing a raw material including a heterogeneous polynuclear complex consisting of Ru and Mn as central metals to prepare a raw material gas, and while introducing the raw material gas to a substrate surface, the gas is heated to have both Ru and Mn deposited, wherein the method uses as a raw material a heterogeneous polynuclear complex as represented by Chemical Formula 1, in which cyclopentadienyl (L) and carbonyl are coordinated to a first transition metal (M.sub.1) being a central metal, and carbonyl is coordinated to a second transition metal (M.sub.2) being a central metal: ##STR00013## wherein M.sub.1 is Ru, and M.sub.2 is Mn; n is 3 or more and 5 or less; R.sub.1, R.sub.2, R.sub.3, and R.sub.5 are hydrogen; and R.sub.4 is an alkyl group with a carbon number of 1 or more and 5 or less.

2. The method for chemical deposition according to claim 1, wherein the total carbon number of all the substituents R.sub.1 to R.sub.5 of the raw material for chemical deposition is 1 or more and 4 or less.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a TG curve of a metal complex produced in an embodiment.

(2) FIG. 2 is a photograph of a cross-section of a metal thin film formed in an embodiment.

(3) FIG. 3 illustrates a Ru/Mn ratio in a metal thin film formed in an embodiment.

DESCRIPTION OF EMBODIMENT

(4) Hereinafter, the best embodiments in the present invention will be described.

(5) In the embodiments, the following five kinds of complexes were synthesized. Synthesized complexes were each evaluated for physical properties, and subjected to a film formation test as a chemical deposition raw material.

(6) ##STR00007##

Example 1

(7) A heterogeneous polynuclear complex (pentacarbonyl[dicarbonyl(.sup.5-cyclopentadienyl)ruthenium]manganese (MnRu)) having ruthenium as a first transition metal and manganese as a second transition metal was produced. The synthesis reaction formula is as described below. Hereinafter, the production process will be described in detail.

(8) ##STR00008##

(9) 1.95 g (5 mmol) of decacarbonyldimanganese and 0.23 g (10 mmol) of metal sodium were added in a flask containing 250 ml of tetrahydrofuran. The solution was stirred at room temperature for 24 hours, a solution obtained by dissolving 3.49 g (10 mmol) of dicarbonyl(.sup.5-cyclopentadienyl)iodoruthenium in 250 ml of tetrahydrofuran was then added, and the mixture was heated at 55 C. and stirred for 18 hours. After completion of the reaction, the reaction product was cooled to room temperature, and concentrated to obtain a muddy reaction mixture. The reaction mixture was extracted with hexane, and purified by column chromatography with silica gel as a carrier and a mixed solvent of hexane and dichloromethane as an eluent. Sublimation purification was performed to obtain 2.94 g (7.0 mmol) of pentacarbonyl[dicarbonyl(.sup.5-cyclopentadienyl)ruthenium]manganese (MnRu) as a specified substance (yield: 70%).

Example 2

(10) A heterogeneous polynuclear complex (pentacarbonyl[dicarbonyl(.sup.5-cyclopentadienyl)iron]manganese (FeMn)) having iron as a first transition metal and manganese as a second transition metal was produced. The synthesis reaction formula is as described below. Hereinafter, the production process will be described in detail.

(11) ##STR00009##

(12) 1.95 g (5 mmol) of decacarbonyldimanganese and 0.23 g (10 mmol) of metal sodium were added in a flask containing 250 ml of tetrahydrofuran. The solution was stirred at room temperature for 24 hours, a solution obtained by dissolving 3.04 g (10 mmol) of dicarbonyl(.sup.5-cyclopentadienyl)iodoiron in 250 ml of tetrahydrofuran was then added, and the mixture was stirred at room temperature for 2 days. After completion of the reaction, the reaction product was cooled to room temperature, and concentrated to obtain a muddy reaction mixture. The reaction mixture was extracted with hexane, and purified by column chromatography with silica gel as a carrier and hexane as an eluent. Sublimation purification was performed to obtain 1.86 g (5.0 mmol) of pentacarbonyl[dicarbonyl(.sup.5-cyclopentadienyl)iron]manganese (FeMn) as a specified substance (yield: 50%).

Example 3

(13) A heterogeneous polynuclear complex (dicarbonyl(.sup.5-cyclopentadienyl)(tetracarbonylcobalt)ruthenium (CoRu)) having ruthenium as a first transition metal and cobalt as a second transition metal was produced. The synthesis reaction formula is as described below. Hereinafter, the production process will be described in detail.

(14) ##STR00010##

(15) 1.71 g (5 mmol) of octacarbonyldicobalt and 0.23 g (10 mmol) of metal sodium were added in a flask containing 250 ml of tetrahydrofuran. The solution was stirred at room temperature for 24 hours, a solution obtained by dissolving 3.49 g (10 mmol) of dicarbonyl(.sup.5-cyclopentadienyl)iodoruthenium in 250 ml of tetrahydrofuran was then added, and the mixture was stirred at room temperature for 18 hours. After completion of the reaction, the reaction product was cooled to room temperature, and concentrated to obtain a muddy reaction mixture. The reaction mixture was extracted with hexane, and purified by column chromatography with alumina as a carrier and a mixed solvent of hexane and dichloromethane as an eluent. Sublimation purification was performed to obtain 2.56 g (6.5 mmol) of pentacarbonyldicarbonyl(.sup.5-cyclopentadienyl)(tetracarbonylcobalt)ruthenium (CoRu) as a specified substance (yield: 65%).

Example 4

(16) A heterogeneous polynuclear complex (dicarbonyl(.sup.5-cyclopentadienyl)(tetracarbonylcobalt)iron (CoFe)) having iron as a first transition metal and cobalt as a second transition metal was produced. The synthesis reaction formula is as described below. Hereinafter, the production process will be described in detail.

(17) ##STR00011##

(18) 1.71 g (5 mmol) of octacarbonyldicobalt and 0.23 g (10 mmol) of metal sodium were added in a flask containing 250 ml of tetrahydrofuran. The solution was stirred at room temperature for 24 hours, a solution obtained by dissolving 3.04 g (10 mmol) of dicarbonyl(.sup.5-cyclopentadienyl)iodoiron in 250 ml of tetrahydrofuran was then added, and the mixture was stirred at room temperature for 2 days. After completion of the reaction, the reaction product was cooled to room temperature, and concentrated to obtain a muddy reaction mixture. The reaction mixture was extracted with hexane, and purified by column chromatography with silica gel as a carrier and hexane as an eluent. Sublimation purification was performed to obtain 2.44 g (7.0 mmol) of dicarbonyl(.sup.5-cyclopentadienyl)(tetracarbonylcobalt)iron (CoFe) as a specified substance (yield: 70%).

Example 5

(19) A heterogeneous polynuclear complex (pentacarbonyl[dicarbonyl(.sup.5-methylcyclopentadienyl)ruthenium]manganese (MnRu)) in which a cyclopentadienyl derivative having one methyl group as a substituent was coordinated was produced. The synthesis reaction formula is as described below. Hereinafter, the production process will be described in detail.

(20) ##STR00012##

(21) 1.95 g (5 mmol) of decacarbonyldimanganese and 0.23 g (10 mmol) of metal sodium were added in a flask containing 250 ml of tetrahydrofuran. The solution was stirred at room temperature for 24 hours, a solution obtained by dissolving 3.65 g (10 mmol) of dicarbonyl(.sup.5-methylcyclopentadienyl)iodoruthenium in 250 ml of tetrahydrofuran was then added, and the mixture was heated at 55 C. and stirred for 18 hours. After completion of the reaction, the reaction product was cooled to room temperature, and concentrated to obtain a muddy reaction mixture. The reaction mixture was extracted with hexane, and purified by column chromatography with silica gel as a carrier and a mixed solvent of hexane and dichloromethane as an eluent. Sublimation purification was performed to obtain 2.59 g (6.0 mmol) of pentacarbonyl[dicarbonyl(.sup.5-methylcyclopentadienyl)ruthenium]manganese (MnRu) as a specified substance (yield: 60%).

(22) Evaluation of physical properties of heterogeneous polynuclear complex: Physical properties were evaluated by TG for the heterogeneous polynuclear complexes produced in Examples 1 and 5. Analysis was performed by observing a change in weight of a complex sample (5 mg) in heating of the sample at a temperature elevation rate of 5 C./min over a measurement temperature range, i.e. from room temperature to 450 C., under a nitrogen atmosphere in TG-DTA2000SA manufactured by BRUKER Corporation. The results are shown in FIG. 1.

(23) The results of TG in FIG. 1 show that for the complexes in Examples 1 and 5, vaporization and decomposition of the complex were started by heating at about 150 C., and thus these complexes had a low decomposition temperature, and were capable of forming a film at a low temperature. After elevation of the temperature to about 200 C., the weight loss was constant. This shows that almost the whole of the raw material was vaporized, and the complexes had a favorable vaporization property.

(24) Film formation test: Next, a film formation test was conducted in which a composite metal thin film was formed by a CVD method with the complex produced in Example 5 as a raw material compound.

(25) The metal thin film was formed on a substrate (15 mm15 mm) with a silicon oxide film deposited on a silicon substrate by use of tetraethoxysilane (TEOS). As a film formation apparatus, a hot wall type thermal CVD apparatus was used. A reaction gas (hydrogen) was fed at a constant flow rate by use of a mass flow controller. Film formation conditions are as described below. The result of observing a cross-section of the metal thin film with a SEM is shown in FIG. 2.

(26) Substrate: SiO.sub.2

(27) Film formation temperature: 250 C.

(28) Sample temperature: 70 C.

(29) Film formation pressure: 5 torr

(30) Reaction gas (hydrogen) flow rate: 10 sccm

(31) Film formation time: 20 minutes

(32) The metal thin film formed in this way was shiny silvery-white, and had a thickness of 74.9 nm. FIG. 2 shows that the metal thin film formed on SiO.sub.2 had a smooth and uniform surface.

(33) M.sub.1/M.sub.2 ratio: the Ru/Mn ratio was analyzed as an abundance of metal elements by an X-ray photoelectron spectroscopy (XPS) method for the metal thin film formed as described above. As a measurement apparatus, KRATOS Axis Nova manufactured by Shimadzu Corporation was used. In this measurement, the thin film (thickness: 74.9 nm) was analyzed in a depth direction from the vicinity of the surface to the upper side of the vicinity of the interface with the SiO.sub.2 film. In the vicinity of the interface with the SiO.sub.2 film, influences of Si and O made it difficult to correctly analyze the Ru/Mn ratio, and the analysis was performed over a range where these influences were small. The results are shown in FIG. 3. The abscissa in FIG. 3 is approximately consistent with a thickness (74.9 nm) from the thin film surface to the upper side of the vicinity of the interface with the SiO.sub.2 film.

(34) FIG. 3 shows that both Ru and Mn were deposited in the metal thin film. The Ru/Mn ratio did not depend on the film depth, and was constant (about 0.15 to 0.2), and thus a thin film having an almost constant metal composition ratio was obtained.

INDUSTRIAL APPLICABILITY

(35) The present invention is capable of forming a composite metal thin film from a single raw material by a chemical deposition method, and it is easy to make the thin film homogeneous and control quality of raw materials. Thus, the present invention can be applied to uses which employ a structure in which a plurality of metal layers are deposited, such as copper diffusion layers in semiconductor devices.